I sympathise MollyAA12, as I don't have children or grandchildren either! I do have one "step grandchild" from my late husbands family - but this grown up young woman does not contact me, since her grandfather passed away.
My (newish) husband and I have just moved from Lincolnshire, where we did have good friends and neighbours, but we keep in touch by email, letter or text.
We are now in the far north of Scotland in a small village. Locals have said hello and seem friendly, but we will be looking to make new friends too!
I found a penfriend on Gransnet, though - and we regularly email each other, so it is possible to make friends on here. I replied directly to the poster, and we have been corresponding now for many months, so don't be put off!
I agree that interests in common are the key, and certainly volunteering is a good way to meet people. I cannot stand for very long, due to Arthritis and Peripheral Neuropathy in my feet, but I love reading, so joining a book club will be something I will look at when libraries are open again. I am considering selling off some of the many books I have (perhaps for Charity), since I cannot donate them to Charity Shops at the moment. I would have to leaflet my village in the hope of getting customers, and would need to check the legality of doing such a thing, I guess.
Good Luck with your search for new friends, be prepared to make the first move, and I'm sure it will work out for you.